Sure, preventable with treatment. Not by prohibiting firearms to 60 million people. I'm not sure why you have such a hard time with the "deemed a danger to themself or others" provision.
Too bad that's not what I said at all. My point wasn't that the number was small, my point was the fact that you're talking about completely blocking the Constitutional right of nearly 60 million Americans based on the actions of 20k.
That's complete bullshit.
And prohibiting firearms wouldn't prevent suicide, either. Though it's a good step... but only if the person is deemed to be a danger to themself.